Rav Moshe Shternbuch has issued an interesting psak about riding the trains in Israel after Shabbos.

Ladaat brings the psak of Rav Shternbuch, Raavad of the Eida Hachareidis, that one should not ride any Israeli train that runs on any line that was worked on on Shabbos until the time of "kdei sheyaasu", the amount of  time it takes to have done that specific work not on Shabbos, wuill have passed. Only after that time has passed will it be ok to ride the trains.

Unfortunately he does not say how much time that is, but he gives the general rule of not riding the train until the amount of time that it went into operation was advanced by the work done on Shabbos has passed.

Rav Shternbuch adds that the authorities should be told about this, as doing so prevents future chilul shabbos as they would try to avoid any boycott, as has happened in other areas in the past.

Interestingly, Rav Shternbuch says there is a discussion about whether something produced via chilul shabbos should be prohibited forever or only for the same amount of time it took to produce on Shabbos. The example given is of someone who dug a grave on Shabbos and that is prohibited forever, but the question is if that was specific for that case but in other scenarios "the amount of time" would be enough or if by other things as well the prohibition is permanent. Rav Shternbuch brings sources that the permanent prohibition was only in that scenario of the grave but not in other cases. Normally "kdei sheyaasu" is all you need.

And therefore, he concludes, riding the train is ok but only after "kdei sheyaasu" will have passed, and to calculate that amount of time one has to be able to figure out how much additional time would have been needed to work on the rail lines had they not worked on them on Shabbos.